Feature Breakdown: Changing how the date and time are displayed

We can change the start time of our simulation to best reflect our simulation’s parameters.

from examples.example_6_simplest_case_storewrapper.ex_6_model_classes_with_vidigi_logging import Trial, g
from vidigi.animation import animate_activity_log
import pandas as pd
import plotly.io as pio
pio.renderers.default = "notebook"
import os

SIM_START_TIME = "08:00:00"

View Imported Code, which has had logging steps added at the appropriate points in the ‘model’ class

import random
import numpy as np
import pandas as pd
import simpy
from sim_tools.distributions import Exponential, Lognormal
from vidigi.resources import VidigiStore


# Class to store global parameter values.  We don't create an instance of this
# class - we just refer to the class blueprint itself to access the numbers
# inside.
class g:
    '''
    Create a scenario to parameterise the simulation model

    Parameters:
    -----------
    random_number_set: int, optional (default=DEFAULT_RNG_SET)
        Set to control the initial seeds of each stream of pseudo
        random numbers used in the model.

    n_cubicles: int
        The number of treatment cubicles

    trauma_treat_mean: float
        Mean of the trauma cubicle treatment distribution (Lognormal)

    trauma_treat_var: float
        Variance of the trauma cubicle treatment distribution (Lognormal)

    arrival_rate: float
        Set the mean of the exponential distribution that is used to sample the
        inter-arrival time of patients

    sim_duration: int
        The number of time units the simulation will run for

    number_of_runs: int
        The number of times the simulation will be run with different random number streams

    '''
    random_number_set = 42

    n_cubicles = 4
    trauma_treat_mean = 40
    trauma_treat_var = 5

    arrival_rate = 5

    sim_duration = 600
    number_of_runs = 100

# Class representing patients coming in to the clinic.
class Patient:
    '''
    Class defining details for a patient entity
    '''
    def __init__(self, p_id):
        '''
        Constructor method

        Params:
        -----
        identifier: int
            a numeric identifier for the patient.
        '''
        self.identifier = p_id
        self.arrival = -np.inf
        self.wait_treat = -np.inf
        self.total_time = -np.inf
        self.treat_duration = -np.inf

# Class representing our model of the clinic.
class Model:
    '''
    Simulates the simplest minor treatment process for a patient

    1. Arrive
    2. Examined/treated by nurse when one available
    3. Discharged
    '''
    # Constructor to set up the model for a run.  We pass in a run number when
    # we create a new model.
    def __init__(self, run_number):
        # Create a SimPy environment in which everything will live
        self.env = simpy.Environment()

        self.event_log = []

        # Create a patient counter (which we'll use as a patient ID)
        self.patient_counter = 0

        self.patients = []

        # Create our resources
        self.init_resources()

        # Store the passed in run number
        self.run_number = run_number

        # Create a new Pandas DataFrame that will store some results against
        # the patient ID (which we'll use as the index).
        self.results_df = pd.DataFrame()
        self.results_df["Patient ID"] = [1]
        self.results_df["Queue Time Cubicle"] = [0.0]
        self.results_df["Time with Nurse"] = [0.0]
        self.results_df.set_index("Patient ID", inplace=True)

        # Create an attribute to store the mean queuing times across this run of
        # the model
        self.mean_q_time_cubicle = 0

        self.patient_inter_arrival_dist = Exponential(mean = g.arrival_rate,
                                                      random_seed = self.run_number*g.random_number_set)
        self.treat_dist = Lognormal(mean = g.trauma_treat_mean,
                                    stdev = g.trauma_treat_var,
                                    random_seed = self.run_number*g.random_number_set)

    def init_resources(self):
        '''
        Init the number of resources
        and store in the arguments container object

        Resource list:
            1. Nurses/treatment bays (same thing in this model)

        '''
        self.treatment_cubicles = VidigiStore(self.env, num_resources=g.n_cubicles)

    # A generator function that represents the DES generator for patient
    # arrivals
    def generator_patient_arrivals(self):
        # We use an infinite loop here to keep doing this indefinitely whilst
        # the simulation runs
        while True:
            # Increment the patient counter by 1 (this means our first patient
            # will have an ID of 1)
            self.patient_counter += 1

            # Create a new patient - an instance of the Patient Class we
            # defined above.  Remember, we pass in the ID when creating a
            # patient - so here we pass the patient counter to use as the ID.
            p = Patient(self.patient_counter)

            # Store patient in list for later easy access
            self.patients.append(p)

            # Tell SimPy to start up the attend_clinic generator function with
            # this patient (the generator function that will model the
            # patient's journey through the system)
            self.env.process(self.attend_clinic(p))

            # Randomly sample the time to the next patient arriving.  Here, we
            # sample from an exponential distribution (common for inter-arrival
            # times), and pass in a lambda value of 1 / mean.  The mean
            # inter-arrival time is stored in the g class.
            sampled_inter = self.patient_inter_arrival_dist.sample()

            # Freeze this instance of this function in place until the
            # inter-arrival time we sampled above has elapsed.  Note - time in
            # SimPy progresses in "Time Units", which can represent anything
            # you like (just make sure you're consistent within the model)
            yield self.env.timeout(sampled_inter)

    # A generator function that represents the pathway for a patient going
    # through the clinic.
    # The patient object is passed in to the generator function so we can
    # extract information from / record information to it
    def attend_clinic(self, patient):
        self.arrival = self.env.now
        self.event_log.append(
            {'patient': patient.identifier,
             'pathway': 'Simplest',
             'event_type': 'arrival_departure',
             'event': 'arrival',
             'time': self.env.now}
        )

        # request examination resource
        start_wait = self.env.now
        self.event_log.append(
            {'patient': patient.identifier,
             'pathway': 'Simplest',
             'event': 'treatment_wait_begins',
             'event_type': 'queue',
             'time': self.env.now}
        )

        # Seize a treatment resource when available
        with self.treatment_cubicles.request() as req:
            treatment_resource = yield req
            # record the waiting time for registration
            self.wait_treat = self.env.now - start_wait
            self.event_log.append(
                {'patient': patient.identifier,
                    'pathway': 'Simplest',
                    'event': 'treatment_begins',
                    'event_type': 'resource_use',
                    'time': self.env.now,
                    'resource_id': treatment_resource.id_attribute
                    }
            )

            # sample treatment duration
            self.treat_duration = self.treat_dist.sample()
            yield self.env.timeout(self.treat_duration)

            self.event_log.append(
                {'patient': patient.identifier,
                    'pathway': 'Simplest',
                    'event': 'treatment_complete',
                    'event_type': 'resource_use_end',
                    'time': self.env.now,
                    'resource_id': treatment_resource.id_attribute}
            )


        # total time in system
        self.total_time = self.env.now - self.arrival
        self.event_log.append(
            {'patient': patient.identifier,
            'pathway': 'Simplest',
            'event': 'depart',
            'event_type': 'arrival_departure',
            'time': self.env.now}
        )


    # This method calculates results over a single run.  Here we just calculate
    # a mean, but in real world models you'd probably want to calculate more.
    def calculate_run_results(self):
        # Take the mean of the queuing times across patients in this run of the
        # model.
        self.mean_q_time_cubicle = self.results_df["Queue Time Cubicle"].mean()

    # The run method starts up the DES entity generators, runs the simulation,
    # and in turns calls anything we need to generate results for the run
    def run(self):
        # Start up our DES entity generators that create new patients.  We've
        # only got one in this model, but we'd need to do this for each one if
        # we had multiple generators.
        self.env.process(self.generator_patient_arrivals())

        # Run the model for the duration specified in g class
        self.env.run(until=g.sim_duration)

        # Now the simulation run has finished, call the method that calculates
        # run results
        self.calculate_run_results()

        self.event_log = pd.DataFrame(self.event_log)

        self.event_log["run"] = self.run_number

        return {'results': self.results_df, 'event_log': self.event_log}

# Class representing a Trial for our simulation - a batch of simulation runs.
class Trial:
    # The constructor sets up a pandas dataframe that will store the key
    # results from each run against run number, with run number as the index.
    def  __init__(self):
        self.df_trial_results = pd.DataFrame()
        self.df_trial_results["Run Number"] = [0]
        self.df_trial_results["Arrivals"] = [0]
        self.df_trial_results["Mean Queue Time Cubicle"] = [0.0]
        self.df_trial_results.set_index("Run Number", inplace=True)

        self.all_event_logs = []

    # Method to run a trial
    def run_trial(self):
        print(f"{g.n_cubicles} nurses")
        print("") ## Print a blank line

        # Run the simulation for the number of runs specified in g class.
        # For each run, we create a new instance of the Model class and call its
        # run method, which sets everything else in motion.  Once the run has
        # completed, we grab out the stored run results (just mean queuing time
        # here) and store it against the run number in the trial results
        # dataframe.
        for run in range(g.number_of_runs):
            random.seed(run)

            my_model = Model(run)
            model_outputs = my_model.run()
            patient_level_results = model_outputs["results"]
            event_log = model_outputs["event_log"]

            self.df_trial_results.loc[run] = [
                len(patient_level_results),
                my_model.mean_q_time_cubicle,
            ]

            # print(event_log)

            self.all_event_logs.append(event_log)

        self.all_event_logs = pd.concat(self.all_event_logs)

my_trial = Trial()

my_trial.run_trial()

4 nurses

SIM_START_DATE = "2024-01-01"
STEP_SNAPSHOT_MAX = 45
LIMIT_DURATION = g.sim_duration
WRAP_QUEUES_AT = 15

event_position_df = pd.DataFrame([
                    {'event': 'arrival',
                     'x':  50, 'y': 300,
                     'label': "Arrival" },

                    # Triage - minor and trauma
                    {'event': 'treatment_wait_begins',
                     'x':  205, 'y': 275,
                     'label': "Waiting for Treatment"},

                    {'event': 'treatment_begins',
                     'x':  205, 'y': 175,
                     'resource':'n_cubicles',
                     'label': "Being Treated"},

                    {'event': 'exit',
                     'x':  270, 'y': 70,
                     'label': "Exit"}

                ])

Run using the all-in-one animation function

Let’s first look at the output if we don’t use the start date or ask for the data to displayed in days, hours and minutes.

animate_activity_log(
        event_log=my_trial.all_event_logs[my_trial.all_event_logs['run']==1],
        event_position_df= event_position_df,
        scenario=g(),
        entity_col_name="patient",
        every_x_time_units=1,
        gap_between_entities=6,
        plotly_height=700,
        frame_duration=200,
        plotly_width=1200,
        override_x_max=300,
        override_y_max=500,
        limit_duration=g.sim_duration,
        wrap_queues_at=25,
        step_snapshot_max=125,
        display_stage_labels=False,
        add_background_image="https://raw.githubusercontent.com/Bergam0t/vidigi/refs/heads/main/examples/example_1_simplest_case/Simplest%20Model%20Background%20Image%20-%20Horizontal%20Layout.drawio.png",
    )

Next, let’s see what happens when we request it in days, hours and minutes using the time_display_units parameter, but don’t specify a simulation start date.

animate_activity_log(
        time_display_units="dhm",
        event_log=my_trial.all_event_logs[my_trial.all_event_logs['run']==1],
        event_position_df= event_position_df,
        entity_col_name="patient",
        scenario=g(),
        every_x_time_units=1,
        gap_between_entities=6,
        plotly_height=700,
        frame_duration=200,
        plotly_width=1200,
        override_x_max=300,
        override_y_max=500,
        limit_duration=g.sim_duration,
        wrap_queues_at=25,
        step_snapshot_max=125,
        display_stage_labels=False,
        add_background_image="https://raw.githubusercontent.com/Bergam0t/vidigi/refs/heads/main/examples/example_1_simplest_case/Simplest%20Model%20Background%20Image%20-%20Horizontal%20Layout.drawio.png",
    )

animate_activity_log(
        event_log=my_trial.all_event_logs[my_trial.all_event_logs['run']==1],
        event_position_df= event_position_df,
        scenario=g(),
        entity_col_name="patient",
        every_x_time_units=1,
        include_play_button=True,
        gap_between_entities=6,
        plotly_height=700,
        frame_duration=200,
        plotly_width=1200,
        override_x_max=300,
        override_y_max=500,
        limit_duration=g.sim_duration,
        wrap_queues_at=25,
        step_snapshot_max=125,
        time_display_units="dhm",
        start_date=SIM_START_DATE,
        display_stage_labels=False,
        add_background_image="https://raw.githubusercontent.com/Bergam0t/vidigi/refs/heads/main/examples/example_1_simplest_case/Simplest%20Model%20Background%20Image%20-%20Horizontal%20Layout.drawio.png",
    )

Finally, we’ll provide a start date for the simulation to display.

animate_activity_log(
        entity_col_name="patient",
        time_display_units="dhm",
        start_date=SIM_START_DATE,
        start_time=SIM_START_TIME,
        event_log=my_trial.all_event_logs[my_trial.all_event_logs['run']==1],
        event_position_df= event_position_df,
        scenario=g(),
        every_x_time_units=1,
        gap_between_entities=6,
        plotly_height=700,
        frame_duration=200,
        plotly_width=1200,
        override_x_max=300,
        override_y_max=500,
        limit_duration=g.sim_duration,
        wrap_queues_at=25,
        step_snapshot_max=125,
        display_stage_labels=False,
        add_background_image="https://raw.githubusercontent.com/Bergam0t/vidigi/refs/heads/main/examples/example_1_simplest_case/Simplest%20Model%20Background%20Image%20-%20Horizontal%20Layout.drawio.png",
    )

Changing the timescale

We could also display the simulation at a daily level. Let’s imagine our simulation represents the number of patients being seen per day instead of per minute.

NOTE: These example animations won’t make a lot of sense as the underlying simulation doesn’t really make sense at a higher resolution than daily! but it gives you some idea of how these parameters can change and their impact on how dates and times are displayed.

animate_activity_log(
        simulation_time_unit="days",
        time_display_units="d",
        start_date=SIM_START_DATE,
        entity_col_name="patient",
        event_log=my_trial.all_event_logs[my_trial.all_event_logs['run']==1],
        event_position_df= event_position_df,
        scenario=g(),
        every_x_time_units=1,
        gap_between_entities=6,
        plotly_height=700,
        frame_duration=2000,
        frame_transition_duration=1000,
        plotly_width=1200,
        override_x_max=300,
        override_y_max=500,
        limit_duration=g.sim_duration,
        wrap_queues_at=25,
        step_snapshot_max=200,
        display_stage_labels=False,
        add_background_image="https://raw.githubusercontent.com/Bergam0t/vidigi/refs/heads/main/examples/example_1_simplest_case/Simplest%20Model%20Background%20Image%20-%20Horizontal%20Layout.drawio.png",
    )

Or per month…

animate_activity_log(
        simulation_time_unit="months",
        time_display_units="m",
        entity_col_name="patient",
        start_date=SIM_START_DATE,
        start_time=SIM_START_TIME,
        event_log=my_trial.all_event_logs[my_trial.all_event_logs['run']==1],
        event_position_df=event_position_df,
        scenario=g(),
        every_x_time_units=1, # Every day
        gap_between_entities=6,
        plotly_height=700,
        frame_duration=1000,
        frame_transition_duration=1000,
        plotly_width=1200,
        override_x_max=300,
        override_y_max=500,
        limit_duration=g.sim_duration,
        wrap_queues_at=25,
        step_snapshot_max=1000,
        display_stage_labels=False,
        add_background_image="https://raw.githubusercontent.com/Bergam0t/vidigi/refs/heads/main/examples/example_1_simplest_case/Simplest%20Model%20Background%20Image%20-%20Horizontal%20Layout.drawio.png",
    )